Thermosensitive release fuse for automatic fire extinguishers



Nov. 9, 1965 B. J. BAKOS 3,216,506

THERMOSENSITIVE RELEASE FUSE FOR AUTOMATIC FIRE EXTINGUISHERS Filed Oct. 17, 1965 2 Sheets-Sheet l INVENTOR. Ben J. Bakos BY WHITEHEAD,VOG 8r LOWE ATTORNEYS Nov. 9, 1965 B. J. BAKOS 3, 6,505

THERMOSENSITIVE RELEASE FUSE FOR AUTOMATIC FIRE EXTINGUISHERS Filed 001:. 17, 1963 2 Sheets-Sheet 2 .IN V EN TOR.

Ben J. Bakos BY WHITEL'IEAD, VOGL LOWE Fig. I2 W 61% AT TORNEYS United States Patent 3,216,506 THERMOSENSITIVE RELEASE FUSE FOR AUIGMATIC FIRE EX'I'INGUISHERS Ben .I. Bakes, Denver, Colo., assignor to The Fire King Company, a corporation of Colorado Filed Get. 17, 1963, Ser. No. 316,938 3 Claims. (Cl. 169-26) This is a continuation in part of my prior application, Serial No. 100,275, filed April 3, 1961, for Ceiling-Type Automatic Fire Extinguisher, now Patent No. 3,107,732. The present application concerns structure disclosed but not claimed in my prior application and other structure which supplements the structure disclosed in my prior application.

This invention relate to automatic chemical fire extinguishers of the type which include a frangible grenade and a striker adapted to break and release the fluid contents of the grenade responsive to an abnormal temperature rise, and more particularly, to a thermosensitive release fuse for concealed and partially concealed grenadetype automatic fire extinguishers.

The primary object of the invention set forth herein is to provide a novel and improved construction of a thermosensitive release fuse for a spring-loaded starting device which is especially useful as a spring-loaded striker for a frangible grenade-type fire extinguisher. Accordingly, the invention will be hereinafter described as a thermosensitive release fuse for a spring-loaded striker, for an automatic fire extinguisher although it is to be understood that such is not a limitation of its use. The objects and description of the prior invention and of the present invention are now setforth.

Another object of the invention is to provide, in a grenade-type automatic fire extinguisher, a novel and improved nozzle unit which effectively combines the nozzle with a grenade-breaking striker, a thermosensitive fuse to release the striker and a spray nozzle into a compact, replaceable unit that may be set into the base of the extinguisher with only the nozzle and fuse being exposed.

Another object of the invention is to provide a novel and improved construction of a grenade-breaking means for an automatic fire extinguisher including a neat and compact arrangement of a spring-loaded grenade-breaking striker and a thermosensitive release fuse which are especially adapted to be mounted in a fire extinguisher as a compact, factory-set unit.

Another important object of the invention is to provide a novel and improved construction of a thermosensitive fuse for the release of a spring-loaded striker for an automatic fire extinguisher and for any like spring-loaded release device that will release by the melting of a lowmelting-point metal whenever the temperature at the fuse rises to the metals melting point, which is simple in form, positive in its action and will not release prematurely as where the metal is weakened by continued warming to temperatures which are less than the critical melting point temperature.

Another object of the invention is to provide a novel and improved thermosensitive release fuse for a springloaded striker and the like release devices which are released by the melting of a low-melting-point alloy, and which is held against the pull of a release shaft by a positive locking means, and which thereby permits the use of various types of low-melting-point alloys that will melt at various selected temperatures but which, in many instances are notably deficient in strength and are not suitable in conventional thermo-release devices.

Yet other objects of the invention are to provide a novel and improved striker unit with a release fuse for grenade- 3,216,506 Patented Nov. 9, 1965 type fire extinguishers and the like which is versatile, simple, neat, inexpensive, reliable, easily installed and easily maintained units.

With the foregoing and other objects in view, all of which more fully hereinafter appear, my invention comprises certain novel constructions, combinations and arrangements of parts and elements, as hereinafter described, defined in the appended claims and illustrated in preferred embodiment in the accompanying drawing, in which:

FIGURE 1 is a fragmentary, sectional, perspective view of a corner of a room, and the attic space above, illustrating my improved automatic fire extinguisher which incorporates the present invention as being properly mounted in the ceiling of the room.

FIGURE 2 is a fragmentary sectional portion of the ceiling as viewed from the indicated line 2-2 at FIG. 1 but on an enlarged scale and illustrating the fire extinguisher as .a side elevational view.

FIGURE 3 is an elevational view of the fire extinguisher per so, on a further enlarged scale with portions thereof being in section and as viewed from the indicated line 33 at FIG. 2 to better illustrate other portions at the interior of the unit.

FIGURE 4 is a sectional plan view of portions of the fire extinguisher and a fragment of the ceiling, as illustrated from the indicated line 44 at FIG. 2.

FIGURE 5 is a fragmentary view of a room, similar to FIG. 1, but illustrating the ceiling as being prepared for the installation of the fire extinguisher by cutting a sized-hole therein and the manner of inserting certain elements through this opening to lock the extinguisher in place.

FIGURE '6 is a sectional elevational view of the exposed base and nozzle-carrying-striker per so, as taken from the indicated line-66 at FIG. 3, but on a further enlarged scale.

FIGURE 7 is an elevational exploded view of the nozzle and striker elements therein.

FIGURE 8 is a fragmentary sectional view, as taken from the indicated line8-8 at FIG. 6, but on a further enlarged scale, to illustrate the construction of the fuse of the striker mechanism.

FIGURE 9 is a perspective view of the elements illustrated at FIG. 8, in an inverted position and in an mtermediate phase of their assembly to depict a preferred method of preparing this fuse.

FIGURE 10 is a perspective view similar to FIG. 9, but illustrating the completed fuse and with broken lines indicating the positioning of parts otherwise hidden from view.

FIGURE 11 is a fragmentary view of amodified 'form of one of the elements illustratedat FIG. 8.

FIGURE 12 is a perspective view, similar to .FIG. 9, but illustrating another modification of the fuse construction.

FIGURE 13 is a fragmentary sectional view, similar to FIG. 8, but showing the addition of keeper elements as a safety feature.

FIGURE 14 is a fragmentary sectional view as taken from the indicated line 14-14 at FIG. 13.

The continued use and demand for chemical fire extinguishers which are commonly known as glass grenades has well established the value of such-extinguishers, and over a number of years there have been continuing improvements to the same. Such improvements relate both to the development of non-toxic and highly effective fire extingiushing fluids and to the improvement of containers for these grenades. One class of such containers include strikers which break the grenades responsive to an abnormal temperature rise and are thus called automatic fire extinguishers. As the worth of such automatic fire extinguishers has been repeatedly demonstrated, the scope of their use has been constantly increased. At many installations the appearance of an exposed fire extinguisher would be undesirable. This has led to several designs of concealed ceiling types of automatic fire extinguishers.

The present invention is an improved and simplified striker unit for an automatic fire extinguisher and especially for a ceiling-type automatic fire extinguisher which is designed for neatness of appearance and ease of installation and maintenance. The outstanding features include a replaceable nozzle construction adapted to spray fluid in a uniformly dispersed manner below the fire extinguisher and striker mechanism within the nozzle having a simplified thermosensitive fuse, all as hereinafter described in detail.

Referring more particularly to the drawing, the improved extinguisher is formed as a funnel-shaped body having its upper portion adapted to hold an ordinary pear-shaped glass grenade G which may be filled with such as carbon tetrachloride or preferably, some other type of equivalent commercial fluids, one type being commonly sold under the trademark VAPYR-X. The upper portion of the body includes a conical, upwardlydiverging wall 21 capped by a cylindrical rim 22 which is sized to receive the grenade G. The grenade is held in position within this container by a strap 23 which extends over the grenade and is locked into diametrically opposing slots 24 adjacent to the upper edge of the cylindrical rim 22. It is contemplated the grenade need not fit into this cavity tightly, and in fact, it is desirable that this fit be somewhat sloppy to permit air from above the container to flow past the wall 21 and the side of the grenade to the lower portion thereof to avoid a vacuum action when fluid is flowing from the extinguisher, as hereinafter described. Flanges or corrugations, not shown, may be formed along the walls of the container to facilitate such air movement if desired.

The lower portion of this body 20 is formed as a threaded, axially-centered spout 25 which is of sufiicient length to extend through an opening in a ceiling C and to be mounted therein by connectors as hereinafter set forth. This container is preferably formed by a spinning operation and with the threads 26 on the spout being rolled as a phase of the spinning operation. When so formed, the threads 26 will be both at the inside and outside of the spout as clearly illustrated at FIG. 3.

This body 20 will be normally placed above the ceiling of a room through a circular opening 27 and in the attic as shown or in the joist space between a ceiling-floor construction and the size of the grenade and its container will be such that it will fit in an ordinary joist space as where standard 2" x 8" floor joists are used. The spout 25, however, extends downwardly through the opening 27 in the ceiling C to a point where its lower edge will be approximately at the bottom surface of the ceiling. The unit is held in position by a circular flange 28 having a threaded inner rim 29 which meshes in the threads 26 of the spout 25. When turned down upon the spout, the flange rests upon the upper surface of the ceiling.

The spout 25 is also secured in position by a conical base 30 which carries a cylindrical, threaded nozzle 31, hereinafter further described, which is turned upon the lower reach of the threaded spout to pull the base 30 and flange 28 together upon the spout and to tightly grip the ceiling C as clearly illustrated at FIG. 2.

To provide for a neat appearance of the unit on the ceiling and for other structural considerations, the base 30 is formed as a comparatively fiat inverted cone with the diameter at its outer periphery being suflicient to bear against the ceiling C and cover the opening 27. The nozzle 31 is mounted in an axially centered sleeve opening 34 at the inverted apex of the base. The sleeve-formed opening 34 terminates within the base portion as an inwardly turned rim 35 and the nozzle 31 includes a mating shoulder 36 near its midpoint which is adapted to seat against the rim 35. The portion of the nozzle 31 above the shoulder 36 is formed as an upstanding-reduced-diameter threaded stub 37 which is adapted to bypass the rim 35 and to be turned into the spout 25. When the body is properly positioned at the ceiling with the spout 25 properly centered, the nozzle 31 may be placed Within the central sleeve 34 of the base and turned into the threaded spout 25 to move the nozzle upwardly into the sleeve 34. This turning will continue until the shoulder 36 of the head bears against the rim 35 of the nozzle and until the nozzle 31 pushes the base against the ceiling to tighten the unit into position.

The nozzle 31 is a hollow, cup-shaped, cylindrical unit having the shoulders 36 at its midpoint and the threaded stub 37 upstanding therefrom, as described. It is also formed with a floor 38 at its base. It follows that the spout 25 of the body, when coupled with the nozzle 31, forms a continuous downward passage which terminates at the floor 38. The nozzle 31 is proportioned so that the lower end adjacent to the floor depends a short distance below the lower apex edge of the base 30 as a narrow, cylindrical exposed ring portion 31'. In this exposed portion 31', there is provided an array of nozzle orifices 39 for releasing fluid which will flow from a broken grenade. These orifices may be arranged in any desired pattern and may be located in the floor 38 as well as in the wall 31. In the construction illustrated, the orifices 39 are directed upwardly somewhat to form a fluid jet trajectory in an upward and outward manner to obtain a maximum coverage of the area below this nozzle head.

This nozzle 31 is conveniently exposed for easy removal and its cup-shaped form provides an ideal container for a spring-loaded striker 40 for breaking the grenade G. Also, a thermosensitive fuse 41 may be conveniently and effectively located below the exposed base of the nozzle.

The stn'ker 40, when positioned in the head 31, must move upwardly against the frangible grenade carried in the body 20 thereabove. It includes a hardened metallic head 42 which has suflicient weight and inertia to easily break the grenade when it is impelled against the grenade.

This head 42 is held on an axially centered shaft 43 threaded into an axially-centered tapped hole 44 in the head 42. The shaft 43 normally extends downwardly and through the nozzle floor 38 for connection with the fuse 41 as hereinafter described. A coiled spring 45 is compressively tensed between the head 42 and the floor 38. It is held in position on the head 42 by a centered stub 46 at the underside of the head which forms a shoulder 47 against which the spring bears. Also, it is held in position by a centered, upstanding boss 48 at the floor 38 which embraces the lower portion of the spring. It follows that whenever the shaft 43 is released to permit the head to move upwardly under the pressure of the spring, the acceleration is intense and by the time it has moved a distance sufiicient to strike the grenade, breakage of the grenade is assured.

The shaft 43 extends downwardly through an orifice 49 at the center of the boss 48 in the floor 38. This orifice 49 is large enough to receive a hard plastic washer 50 which is in the general form of an inverted cylindrical T with an annular flange 50 of the T fitting into a bearing against the undersurface of the inverted cup-formed boss 48. The cylindrical leg of the T includes a passageway 52 through it through which the shaft 43 slidably extends. It is contemplated that this washer 50 will fit tightly in the orifice 49 and that the diameter of the passageway 52 is such that there will not be an unreasonably large flow of fluid downwardly therethrough should the shaft pass from this passageway by action of the spring 45 moving the head upwardly to the grenade. However, if such leakage is not desired, a simple closure means can be provided or the length of the washer may be such as to retain the shaft 43 within its central passageway 52 even after the head 4-2 has moved upwardly and broken the grenade.

The shaft is held in position by an improved thermosensitive fuse 41, which is in a general form suggestive of a collar button having a button-shaped body 53 carried below an axially centered stem 54. A passageway 55 extends through the stem and body to receive and hold the end of the shaft 43, and when properly positioned, the end of the stem 54 bears against the underside of the T flange 51 of the washer 50 as illustrated at FIG. 6'. The fuse thus holds the shaft and the striker means in position for ultimate operation with the spring 45 being tightly compressed between the floor 38 and the striker 42.

The body 53 of the fuse 41 flares outwardly from the stem 54 and is located a short distance below the floor 38 of the nozzle at a convenient position to sense air temperatures and even receive effects of heat radiation. The body 53 thus presents an inverted cup form, and a cavity 56 is located at its underside. This cavity is filled with a low-melting-point metal 57, which may be a suitable alloy of bismuth such, for example which includes 50 percent bismuth, 28.10 percent lead, and 21.90 percent tin, and which melts at 203 degrees F., to normally hold the end of the shaft 43 in place but to release when abnormal temperatures melt the metal. Any metal which would effectively solder to the shaft 43 would hold it in place under moderate tension and the pull on the shaft, imposed by the compression of spring 45 could be held by a low-melting-point metal. However, it was discovered that any pull for a substantial period of time could cause the metal to release. This led to the development of an improved holding means in the fuse 41 as now described.

This holding means includes an annular groove 58 near the end of the shaft 43 having the side 59 adjacent to the end of the shaft inclined at an angle sufficient to create an outward thrust against any element lying in the groove and abutting against the inclined surface 59, whenever the shaft is pulled in an axial direction as by the action of the spring 45. Suitable abutting elements are formed as a pair of short pins 60 which are sized to lie in the inverted cavity 56 and to extend into the annular groove 58 at opposing diametrical positions. When these pins are restrained laterally, they lock the shaft in place. They are easily held in position by the low-melting-point metal 57 which, when frozen, effectively prevents them from moving laterally, as from the position illustrated at FIG. 8. Thus, the pins 60 lock and hold the end of the shaft 43 in place without imposing any shear or tension on the low-melting-point metal 57. However, when the metal 57 is melted, as from an abnormal temperature rise in the surrounding environment, the pins 60 are no longer restrained and will move laterally to release the shaft. The inclined side 59 will assure this action. Another advantage of the simple cup form of the button body 53 is that the low temperature point metal is effectively contained within the cavity 56 with only the lower surface being exposed.

FIGURES 9 and 10 illustrate a simplified and highly effective manner of forming the locking pins 60 to hold the shaft 43 in place in the cavity 56. A wire 61 is formed as a U-shaped member having the ends 60' thereof turned at an angle to ultimately form the pins. This U-shaped member may be formed as a tweezer-like unit and act to spring the ends 60' together. Thus, to form the connection of the shaft 43 and fuse body 53, the elements are inverted, the ends 60 are set into the cavity 56 to pinch the shaft 43 at the groove 58, as clearly illustrated at FIG. 9. The next step is to fill the cavity 56 with the low temperature-melting-point metal 57. Once the metal 57 is frozen, the extended loop of the wire 61 may be cut off at 51 adjacent to the surface of the metal 57, as illustrated at 'FIG. 10, to form the individual pins 60' which will hold the shaft in place.

Another variation which may be used in this construction is illustrated at FIG. 12 where, in lieu of the pins above described, a simple spring type shaft key 62 may be placed at the groove 58 of the shaft with the sides of the key abutting against the base of the cavity. Such a key will easily spring apart whenever there is a tension upon the shaft because of the inclination of the side 59 of the shaft groove. However, this key 62 will remain tightly in position whenever the pocket of the button is filled with the low temperature metal 57.

FIGURE 11 illustrates a variation of the construction of the shaft 43 where notches 63 are cut in the shaft instead of an annular groove heretofore described. The pins or 60 are set in these notches and the final result is the same. This construction is slightly more expensive but the strength of the shaft is increased since the groove 58 is the weakest point.

The construction illustrated at FIGS. 13 and 14 shows the use of a pair of hook-like keepers 7 0 which are adapted to supplement the holding of the .pins 60 by the low melting-point metal 57. Some types of low-melting-point alloys are deficient in strength and while melting does not occur during the heat of a normally hot day, the metal nevertheless may become softened to the point where it will yield slightly to the pressure of the shaft 43 against the pins 60 and it is possible that over a period of time, this yielding may increase to the point where the pin will let go. The keepers 70, however, resist the spreading apart action and facilitate holding the pins 60 in place until the low-melting-point metal 57 is actually melted.

I have now described my invention in considerable detail and it is obvious that others skilled in the art can devise alternate and equivalent constructions which are nevertheless within the spirit and scope of my invention. Hence, I desire that my protection be limited, not by the constructions illustrated and described herein, but only by the proper scope of the appended claims.

I claim:

1. A fuse for a spring-loaded striker and the like adapted to be held under tension by a shaft to hold the shaft and to be released to release the shaft, and including, in combination therewith, (a) a notch about the end of the shaft; (b) a button having a cavity therein and a passageway therethrough and being adapted to be mounted upon the end of the shaft with the shaft extending through the passageway and with the notch lying within the cavity; (c) a pair of pins adapted to lie within the cup cavity with a pin being at each side of the shaft and lying within said notch to lock the shaft to the button but to move from the notch to release the shaft from the button responsive to the pull of the shaft against the button; (d) a keeper in the general form of a U-shape when viewed along an edge thereof adapted to lie in the cavity and to embrace the pins when the pins are in said notch; and, (e) a low-melting-point alloy adapted to fill the cavity to thereby solder the button to the shaft, encase the pins therein in a holding position with each pin in the shaft notch and to hold the keeper upon the pins in position for holding the pins in the notch.

2. A thermosensitive spring-loaded striker means mounted upon a plate member having an orifice therethrough adapted to release a tensed spring means at one side of the plate responsive to a rise in temperature to a selected temperature level at the other side of the plate and comprising a spring adapted to rest upon the member over the orifice, a striker head carried upon the spring, a shaft connected to the striker head at the axial center of the spring and extending through the orifice with the spring being compressed between the head and the plate, and with one end of the shaft projecting beyond the surface of the plate, said shaft including a notch about the end portion thereof, a button having a cavity therein and a passageway therethrough and being adapted to be mounted upon said shaft with the shaft extending through the passageway with the notches within the cavity, a pair of pins adapted to lie within the button cavity with each pin lying in the notch to lock the shaft end in the cavity, but to move out of the notch to release the shaft from the pins responsive to a pull of the shaft, a keeper of a general U-shape when viewed along an edge thereof, adapted to be placed over the pins, and a low-meltingpoint alloy filling the cavity to thereby solder the button to the shaft, encase the pins within the cavity in the holding position in the shaft notch and secure the keeper over the pins, whereby to prevent movement of the pins as from creep of the alloy and release of the shaft only by melting of the alloy.

3. A fuse for a spring-loaded striker and the like adapted to be held under tension by a shaft, to hold the shaft and to be released to release the shaft, and including in combination therewith; (a) a notch about the end of the shaft; (b) a button having a cavity therein and a passageway therethrough and being adapted to be mounted upon the end of the shaft with the shaft extending through the passageway and with the notch lying within the cavity; (c) a pin means adapted to lie within the cup cavity and to normally lie within said notch to lock the ,shaft to the button, but to move from the notch to release the shaft from the button responsive to a pull of the shaft against the button; (d) a keeper means adapted to be placed within the cavity with portions embracing the end of the shaft, and with other portions being turned to lie against the pin means and to hold the pin means within said notch with the keeper means in position; and (e) a low-melting-point alloy adapted to fill the cavity to thereby solder the button to the shaft, encase the pin means therein to a holding position in the shaft notch and to hold the keeper means in position for holding the pin means in the notch.

References Cited by the Examiner UNITED STATES PATENTS 1,860,074 5/32 Bronander l6926 1,892,724 1/33 Green l6926 1,969,880 8/34 Evans et a1 l6926 2,218,85'7 10/40 Roessner l6926 2,412,491 12/46 Angell l6926 2,580,810 1/52 Mathias 1'69-26 3,048,913 8/62 Ball 29-155.5 3,140,539 7/64 Holtzman 29497.5

EVERETT W. KIRBY, Primary Examiner. 

3. A FUSE FOR A SPRING-LOADED STRIKER AND THE LIKE ADAPTED TO BE HELD UNDER TENSION BY A SHAFT, TO HOLD THE SHAFT AND TO BE RELEASED TO RELEASE THE SHAFT, AND INCLUDING IN COMBINATION THEREWITH; (A) A NOTCH ABOUT THE END OF THE SHAFT; (B) A BUTTOM HAVING A CAVITY THEREIN AND A PASSAGEWAY THERETHROUGH AND BEING ADAPTED TO BE MOUNTED UPON THE END OF THE SHAFT WITH THE SHAFT EXTENDING THROUGH THE PASSAGEWAY AND WITH THE NOTCH LYING WITH THE CAVITY; (C) A PIN MEANS ADAPTED TO LIE WITHIN THE CUP CAVITY AND TO NORMALLY LIE WITHIN SAID NOTCH TO LOCK THE SHAFT TO THE BUTTOM, BUT TO MOVE FROM THE NOTCH TO RELEASE THE SHAFT FROM THE BUTTOM RESPONSIVE TO A PULL OF THE SHAFT AGAINST THE BUTTON; (D) A KEEPER MEANS ADAPTED TO BE PLACED WITH THE CAVITY WITH PORTIONS EMBRACING THE END OF THE SHAFT, AND WITH OTHER PORTIONS EMBRACKING THE LIE AGAINST THE PIN MEANS AND TO HOLD THE PIN MEANS WITHIN SAID NOTCH WITH THE KEEPER MEANS IN POSITION; AND (E) A LOW-MELTING-POINT ALLOY ADAPTED TO FILL THE CAVITY TO THEREBY SOLDER THE BUTTON OF THE SHAFT, ENCASE THE PIN MEANS THEREIN TO A HOLDING POSITION IN THE SHAFT NOTCH AND TO HOLD THE KEEPER MEANS IN POSITION FOR HOLDING THE PIN MEANS IN THE NOTCH. 